Why these dependencies are getting rearranged in build.gradle ? : Android Studio

I'm using Android Studio 2.3. In my app level build gradle, I have these dependencies.

    compile 'com.android.support:appcompat-v7:25.3.1'
    compile 'com.android.support:design:25.3.1'
    compile 'com.github.bumptech.glide:glide:3.6.1'
    compile 'com.android.support.constraint:constraint-layout:1.0.2'
    compile 'com.google.firebase:firebase-core:10.2.4'
    compile 'com.google.firebase:firebase-database:10.2.4'
    compile 'com.google.firebase:firebase-storage:10.2.4'
    compile 'com.google.firebase:firebase-auth:10.2.4'
    compile 'com.firebaseui:firebase-ui-auth:1.2.0'
    compile 'com.google.firebase:firebase-messaging:10.2.4'
    compile 'com.google.android.gms:play-services-auth:10.2.4'
    testCompile 'junit:junit:4.12'

Not all the time, but some times when I run my app after few modifications in my source code (Activities basically). It rearranges the order as shown below and gives me a build error in LogCat. why ?

compile
    'com.android.support:appcompat-v7:25.3.1'compile
    'com.android.support:design:25.3.1'compile
    'com.github.bumptech.glide:glide:3.6.1'compile
    'com.android.support.constraint:constraint-layout:1.0.2'compile
    'com.google.firebase:firebase-core:10.2.4'compile 'com.google.firebase:firebase-database:10.2.4'
    compile 'com.google.firebase:firebase-storage:10.2.4'
    compile 'com.google.firebase:firebase-auth:10.2.4'
    compile 'com.firebaseui:firebase-ui-auth:1.2.0'
    compile 'com.google.firebase:firebase-messaging:10.2.4'
    compile 'com.google.android.gms:play-services-auth:10.2.4'
    testCompile 'junit:junit:4.12'